The goal of the UCLA-CGEP is to investigate the hypothesis that the cellular mechanisms of action identified for Putative Environmental Toxicants (PETs) contribute to a significant increase in PD risk;this project will focus on investigations in rodents. Our group identified specific cellular mechanisms that are affected by PETs: the proteasome, microtubule integrity, and aldehyde dehydrogenase detoxification. Together with altered VMAT function/expression that influences dopamine balance, these pathways-may affect the vulnerability of DA neurons to neurodegeneration. We propose to use our complementary expertise with molecular, neurochemical, electrophysiological, and viral gene delivery approaches to determine whether these cellular mechanisms are affected by PETs in vivo in rodent brains and identify additional molecular and functional alterations induced by PETs that can contribute to increased vulnerability of DA neurons. Using PET treatment regimens that lead to mild dysfunction of DA neurons we will determine whether PETs alter levels of K48 and K63 ubiquination in tissue and increase levels of mitochondrial aldehyde dehydrogenase substrates in DA neurons. We will identify new genes involved in the cellular mechanism of actions of PETs by assessing transcriptome changes induced by PETs in nigrostriatal DA neurons isolated by laser capture microdissection, and use slice electrophysiology to identify the mechanism of action of PETs on the cellular properties of DA neurons. Finally, we will assess the role of regulation of DA cytoplasmic levels in modulating PET toxicity by examining the effects of virally or pharmacologically induced alterations of VMAT in rats treated with PETs. These in vivo animal experiments will provide a link between molecular mechanisms identified in projects 1 and 2 and the toxicity of compounds found by our group (Project 4) to increase PD risk in humans. In turn, the transcriptome and electropysiological analyses in Project 3 may point to new cellular pathways to be investigated in genetic studies in Drosophila (Project 2) and in humans (Project 4).